Raman Spectroscopic Study of Crystallization from Solutions Containing MgSO₄ and Na₂SO₄: Raman Spectra of Double Salts

Abstract

Mg(2+), Na(+), and SO(4)(2-) are common ions in natural systems, and they are usually found in water bodies. Precipitation processes have great importance in environmental studies because they may be part of complex natural cycles; natural formation of atmospheric particulate matter is just one case. In this work, Na(2)Mg(SO(4))(2)·5H(2)O (konyaite), Na(6)Mg(SO(4))(4) (vanthoffite), and Na(12)Mg(7)(SO(4))(13)·15H(2)O (loeweite) were synthesized and their Raman spectra reported. By slow vaporization (at 20 °C and relative humidity of 60-70%), crystallization experiments were performed within small droplets (diameter ≤ 1-2 mm) of solutions containing MgSO(4) and Na(2)SO(4), and crystal formations were studied by Raman spectroscopy. Crystallization of Na(2)Mg(SO(4))(2)·4H(2)O (bloedite) was observed, and the formation of salt mixtures was confirmed by Raman spectra. Bloedite, konyaite, and loeweite, as well as Na(2)SO(4) and MgSO(4)·6H(2)O, were the components found to occur in different proportions. No crystallization of Na(6)Mg(SO(4))(4) (vanthoffite) was observed under the crystallization condition used in this study.

The Raman spectra of the Na2SO4‐K2SO4 system: Applicability to soluble salts studies in built heritage

“…However, in some conditions (saturated solution lead to majority of Phase V), the formation of the called Phase III is also possible. This last compound has an orthorhombic structure, which despite of being considered as metastable, can be quite stable at room temperature depending on the crystallization conditions . Continuing with the dehydration process, thenardite (Phase V) can lead to the formation of Phase I, which has a hexagonal structure.…”

Exploration of Insulin Amyloid Polymorphism Using Raman Spectroscopy and Imaging

“…with and without salts before heating in order to investigate any spectral differences from native insulin caused by salts effects. There were no specific changes to protein structures caused by salt effects except for the small peak at 980 cm -1 due to the symmetric stretching vibration of the SO 4 2of the salt (47,48). Time-dependent spectral variations in the insulin samples with the salts, showing the secondary structural change from α-helix to β-sheet with heating were also observed in the amide I and III wavenumber regions with the formation of amyloid fibrils.…”

Identification of minerals and organic materials in Middle Eocene ironstones from the Bahariya Depression in the Western Desert of Egypt by means of micro‐Raman spectroscopy

“…Raman spectroscopy alone, or in combination with other techniques, has also been successfully applied to mineral and organic material characterization and identification. [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] Determination of the chemical composition of various meteorites [28][29][30] and rocks derived from the Earth's surface, [14][15][16]31] discrimination between closely related minerals [17,18] or detection of biosignatures from geological specimens [32,33] are possible by means of Raman spectroscopy.…”

“…Investigation of pigments used in paintings, of varnishes and binding media utilized for art conservation or discrimination between genuine and fake artifacts and gems are common applications of Raman spectroscopy in this field. Raman spectroscopy alone, or in combination with other techniques, has also been successfully applied to mineral and organic material characterization and identification . Determination of the chemical composition of various meteorites and rocks derived from the Earth's surface, discrimination between closely related minerals or detection of biosignatures from geological specimens are possible by means of Raman spectroscopy.…”